While having a very flexy rear suspension will will actually cause the front to flex less. (has to do with the truck's angle determined by the two spring rates, one gives more the other less. This is compouned when the truck is tilting as your suspension's direction of travel is not the same as the direction of force on it) When you have IFS you need all you can get so go for it. Even with less flexy springs, as the front wheels negotiate uneven terrain, the front, the heavier part of the truck, will still flow their angle and just lift a rear wheel sooner.

The real solution is to lessen the front spring rate.

I have flexy rear springs, longer shackles, and longer shocks. I'm happy with it.

Frank.